Circuit interrupter



Jan. 18, 1949. p STROM 2,459,599

CIRCUIT INTERRUPTER Filed Sept. 20, 1944 I5 Sheets-Sheet 1 WITNESSES: INVENTOR ZZZ Max A. P. STROM 2,459,599

CIRCUIT INTERRUPTER Jan. 18, 1949.

Filed Sept. 20, 1944 3 Sheets-Sheet 2 WITNESSES: 52 0? INVENTOR I X/Zff/ ATTORNE Patented Jan. 18, 1949 CIRCUIT INTERRUPTER Albert P. Strom, Forest Hills, Pa., asoignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 20, 1944, Serial No. 554,898

8 Claims. (Cl. 200-150) This invention relates to circuit interrupters in general and, more particularly, to arc extinguishing structures therefor.

A general object of my invention is to provide an improved circuit interrupter which will more effectively interrupt the vcircuit therethrough than has been achieved heretofore.

A more specific object is to provide an improved circuit interrupter in which an arc is drawn through an orifice and rotated therein while being simultaneously subjected to a fluid blast through the orifice. The fluid blast directed through the orifice may be either a gas or an insulating are I the pair of cooperable ring-shaped contacts while being subjected to a fluid blast passing through the orifice.

Another object is to provide an improved circuit interrupter having an improved orifice construction in which one of the cooperable contacts has an insulating fluid directing member associated therewith to symmetrically guide the fluid blast through the orifice about the contact. Preferably the fluid directing member at least partially extends within the orifice to cooperate with the walls of the orifice so that the point of maximum restriction through the orifice is closely adjacent to said contact having the fluid directing member associated therewith.

Another object is to provide an improved circuit interrupter having an improved orifice construction in which an are drawn through the orifice is rotated therein. Preferably coil means are utilized to create a magnetic field in the vicinity of the orifice, which coil means are short-circuited in the closed circuit position of the interrupter.

Another object is to provide an improved circuit interrupter of the rotating arc type in which improved constructional details in the contact structure are employed to bring about improved and more economical operation.

Another object is to provide an improved circuit interrupter in which an arc is drawn through an orifice and subjected to a flow of liquid passin through the orifice. I provide means for adding static superimposed pressure on both sides of the orifice. Preferably the means for furnishing the static superimposed pressure comprises a gaseous region disposed above the liquid 2 level which is raised to an elevated pressure. Also preferably the arc drawn through the orifice is simultaneously rotated therein while being subjected to the liquid blast passing through the orifice.

Further objects and advantages will readily become apparent upon a reading of the following specification taken in conjunction with the drawings, in which:

Figure 1 is an elevational view, partially in section, of a circuit interrupter embodying my invention, the parts being shown in the closed circuit position;

Fig. 2 is an enlarged vertical sectional view through the left-hand are extinguishing unit of Fig. -1, the parts also being shown in the closed circuit position;

Fig. 3 is an enlarged fragmentary vertical sectional view of the upper portion of the are extinguishing unit shown in Fig. 2, the parts being shown. in the fully open circuit position of the interrupter;

Fig. 4 is a sectional view taken along the line IV--IV of Fig. 2;

Fig. 5 is a sectional view taken along the line V-V of Fig. 3;

Fig. 6 is a vertical sectional view through an arc extinguishing unit of modified construction embodying my invention, the parts being shown in the closed circuit position; and

Fig. 7 is a sectional view taken alon the line VII-VII of Fig. 6.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference numeral I designates a tank filled to the level 2 with a suitable arc extinguishing fluid 3, in this instance circuit breaker oil. Depending from the cover 4 of the tank I are two insulating bushings 5, 6 through which extend terminal studs I, 8. The terminal studs I, 8 threadedly secure in position two are extinguishing units 9 of identical construction which are electrically interconnected in the closed circuit position, as shown in Fig. l by a conducting bridging bar Ill reciprocally actuated in a vertical direction by an insulating operating rod I I actuated by suitable mechanism not shown, The left-hand are extinguishing unit 9 is more clearly illustrated in Figs. 2-5, inclusive.

Referring more particularly to Fig. 2, the reference numeral I3 designates a contact foot threadedly secured to the terminal stud I and to which is rigidly secured an annular stationary contact I4. The annular stationary contact I4 is preferably hollow having ports I5 disposed at its upper end. The upper portion of the 3 annular stationary contact M has a stud portion it which passes through a plate portion II integrally formed with the contact foot l3. Nuts l3 threadedly secured on the stud portion l3 rigidly secure the stationary contact l4 in position. 7

The plate portion II of the contact foot l3 closes the upper end of an insulating casing I3, which is secured to the contact foot |3 by suitable fastening means in this instance comprising bolts 20. The lower end of the casing I3 is closed by a metallic plate 2| rigidly secured in place by bolts 22.

Cooperable with the annular stationary contact I4 is a movable contact 23 having a ringshaped arcing portion 24 (Fig. '3), in this instance comprising a metallic disc composed of a suitable arc resisting material. The movable contact 23 also has an annular contacting portion 25, in this instance comprising a brass sleeve fixedly secured to the movable contact 23 by pins 23, as more clearly shown in Fig. 3. The brass sleeve is slotted at 21 to render it resilient thus forming the fingers 25. Also the annular stationary contact I4 is slotted at 28 so that in the closed circuit position of the interrupter, as shown in Fig. 2, when the annular contacting portion 25 engages the annular stationary contact N there will be formed resilient contact pressure between the two.

Inserted into the movable contact 23, which is preferably made of copper, is a steel stud 23 which serves the function of holding in position the ring-shaped contact 24 and an insulating conically-shaped fluid directing member 30, more clearly shown in Fig. 3. The fluid directing member symmetrically guides the fluid blast, in this instance oil, adjacent the ringshaped contact 24 during the opening operation. It also, in addition to preventing the are from lingering in the center of the orifice, fills up the plate 2| in the full open circuit position of the movable contact 23.

The bridging bar III has a movable disconnect I contact 43 associated therewith which moves in a bore 41 provided in the extremity 43 of the bridging bar III. A smaller bore 43 in registration with the bore 41 contains a compression spring 50 which biases the movable disconnect contact 46 upwardly until the nuts 5| strike the lower portion 52 of the extremity 48. The nuts 5| secure a flexible conductor 53 to the movable disconnect contact 46, the other end of the hexible conductor 53 being secured by a bolt 34 to the bridging bar l0.

Thus in the closed circuit position of the interrupter the extremity 48 of the conducting bridging bar It) maintains the plate 31 in its raised position, thereby compressing the compression spring 39. Also the movable discon-- nect contact 46 seated on a shoulder 55 of the extremity 48 forces the movable contact 23 upwardly against the downward biasing action exerted by the compression spring 45.

From the above description it will be apparent that in the closed circuit position of the interrupter as shown in Figs. 1 and 2, the electrical circuit therethrough comprises terminal stud 7, contact foot I3, plate portion H integrally formed with contact foot l3, annular stationary contact l4, annular contacting portion 25 of movable contact 23, movable contact 23 to movable disconnect contact 46, through the flexible conductor 53 and through the conducting bridging bar III to the other are extinguishing unit 9. The electrical circuit extends through the right-hand arc extinguishing ,unit 3 in a manner identical to its passage through the left-hand arc extinguishing unit 9.

An insulating conduit 56 cooperates with medead spot which is associated with a radially converging fluid flow.

Preferably I employ means forming an orifice adjacent the point of contact separation. In this instance the means comprises a suitably shaped annular member 3| having a configuration shown in Fig. 3 which rests upon an insulating sleeve 32 also disposed in the interior of the casing l9. Movable within the sleeve 32, which forms a piston chamber, is an insulating piston 33 actuated by piston rods 34 which pass through apertures 35 formed in the plate 2|. The lower ends of the piston rods 34 are threaded and cooperate with nuts 33 to secure the lower ends of the piston rods 34 to a metallic plate 31 having an aperture 38 formed therein.

Disposed between the plate 2| and the plate 31 is a compression spring 33 which serves the function of biasing the piston rods 34 and hence the piston 33 in a downward direction asviewed in Fig. 2. The downward movement of the piston 33 is determined by an upstanding ringshaped portion 40 integrally formed with the metallic plate 2|.

The movable contact 23 has two flanges,-

42 rigidly secured thereto. The movable contact 23 passes through an aperture 43 provided in the plate 2| and has a flange portion 44 formed at its lower end which serves as a lower seat for acompression spring 45 which serves the function of biasing the movable contact 23 downwardly towards its full open circuit position as shown in Fig. 3, the flange 42 striking the cured in the walls of the casing l3 to form intercommunication between the region 59 below the piston 33 and the region 60 adjacent the annular stationary contact i4. Preferably exhaust ports 6| are provided through the walls of the casing l3 and also through the insulating sleeve 32.

Fixed to the annular stationary contact I4 is a spider 62 which is threadedly secured to a sleeve-shaped member 63 composed of a suitable magnetic material, in this instance iron. If desired, set screws 64 may be employed after the spider 62 has been threadedly secured in place to the magnetic yoke member 83. Coil means, in this instance comprising a coil 65, is employed to provide a radial magnetic field in the vicinity of the separated contacts so that the arc 66 (Fig. 3) established between the ringshaped contact 24 and a ring-shaped stationary arcing contact 61 may be rotated therearound. One terminal of the coil 65 is electrically connected at 68 (Fig. 3). to the magnetic yoke 33 and hence through the spider 62 to the stationary contact l4. The other end of the coil 35 is connected to a brass ring coil terminal 33 which is electrically connected by screws 13 to the stationary ring-shaped arcing contact 31, which is disposed intermediate the annular stationary contact l4 and the orifice II on a first side of said orifice II.

Threadedly secured to the magnetic yoke 33 is a ring-shaped member 12 composed preferably I of nonmagnetic metal or insulating material.

. II and movable contact 23 games distance beyond coil it toward the discharge side of the interrupter in order to intensify the radial magnetic field set up by coil II in the vicinity of the separated contacts.

The operation of this embodiment of inv invention will now be explained. To break the electrical circuit passing through the interrupter, the operating rod II is moved downwardly by suitable means. This permits the compression springs 3|, 44 to force the piston downwardly, the movable disconnect contact 44 remaining in engagement with the flange portion 44 of the movable contact 23. As the piston 33 moves downwardly fluid, in this instance oil, is caused to pass upwardly through the conduit 44 to the region Ill, downwardly through the perforatims 14 provided in the spider t2 and downwardly through the orifice H from the first side thereof to the second side thereof.

As the annular contacting portion or fingers 25 of the movable contact 23 pass below the lower ends of the fingers I4, the fingers II spread out and make contacting engagement with the ring-shaped arcing contact 41. The coil 45 is now in series circuit. Further downward movement of .the movable contact 2! draws an are 66 between the ring-shaped stationary arcing contact 81 and the ring-shaped arcing portion 24 of movable contact 23 as shown in Fig. 3. Fig. 3 represents the fully open position of the contacts when the flange 42 strikes the plate 2|. However, the are I may have been extinguished before this fully open position is reached. Now the electric circuit extends from the stationary contact i4 through the metallic spider 62 through the magnetic yoke member 63, coil 65, brass ring terminal coil 4!, screws 10, ring-shaped stationary arcing contact 61 through the are 56 (Fig. 3) to the ringshaped arcing contact 24. The radial magnetic field set up by the coil 65 and intensified by the magnetic structure which comprises the magnetic sleeve 63 causes a rotation of the are 68 around the contacts 41, 24 while it is positioned within the orifice H and while it is being simultaneously subjected to a blast of fluid. in this instance oil, passing downwardly through the orifice H. The result is a rapid extinction of the are 68 and a consequent breaking of the electrical circuit passing through the interrupter.

Following the interruption of the electrical circuit the movable disconnect contact 48 separates from the movable contact 23 to insert an insolating gap into the circuit, the bridging bar I moving downwardly to a position indicated by the dotted line 11 of Fig. 1.

From the foregoing description it will be apparent that I have provided an improved circuit interrupter of the orifice type in which I draw an are through the orifice and rotate said are while it is positioned therein utilizing a radial magnetic field set up by a coil which is short-circuited in the closed circuit position of the interrupter. Preferably the point of maximum restriction through the orifice, designated by the reference numeral H, is positioned closely adjacent to the ring-shaped arcing contact 24. The point of maximum restriction is near the discharge end of the arc so that the arc lies essentially, in a region where pressure is above atmospheric pressure. This increases the dibifurcated at 88 having the electric strength of the arc and improves interruption. It will also be observed that the insulating follower 30 extends partially within the orifice H and cooperates with the walls of the orifice in directing symmetrically the fiuid fiow adiacent the ring-shaped contact 24.

In the embodiment of my invention shown in Figs. 8 and 7, the arc extinguishing features adjacent the orifice II are the same as previously described. However, a gaseous region 80 disposed above the oil liquid level III is .raised to an elevated static pressure which may approach the order of 350 to 400 pounds per square inch. Thus the oil which is disposed within the interrupting structure is subjected to the above static superimposed pressure caused by compressing the gas within the region 80 to the above pressure by means of the gaseous pressure supply conduit 94. The movable contact 23 is biased upwardly by a compression spring 4| and is forced to the closed position by a fork l2 integrally formed with a lever 83 pivotally mounted at 84 to a bracket 85 secured at its lower end by a bolt 86 to the casing 81.

The right-hand end of the lever 83 is also legs of the bifurcated portion 88 engaging a metallic sleeve 80 which surrounds an operating rod 90 which may be actuated by suitable means not disclosed. The operating rod 90 extends through a piston chamber 9| and has secured thereto a piston 02 which causes the desired circulation of oil through the orifice 'Il.

During the opening operation, the operating rod 90 is moved downwardly, to cause a downward movement of the piston 92 within the piston chamber 9i thereby causing the desired circulation of oil through the orifice H and meanwhile permitting the compression spring 45 to force the movable contact 23 upwardly drawing an arc and extinguishing the same in the manner as previously described in connection with the interrupter shown in Figs. 1-5. This embodiment of my invention is largely concerned with the maintaining of a desired static superimposed pressure above the oil level which thereby causes pressure to exist on both sides of the orifice H. An over-pressure valve 95 limits the pressure within region 80. The result of utilizing the static superimposed pressure, which may be of the order of 400 pounds per square inch, causes increased eiTective operation of the interrupter.

From the foregoing description it will be apparent that I have provided an orifice type circuit interrupter in which the arc is established within an orifice and rotated therein while being simultaneously subjected to a fluid blast. By providing the above described improved constructional details the coil used for providing the radial magnetic field is short-circuited in the closed circuit position of the interrupter and hence energy dissipated through heat is consequently minimized. By utilizing static superimposed pressure, in this instance comprising a gaseous region 80 raised to a suitable high elevated static pressure, interrupting performance is increased.

Although I have shown and described specific structures, it is to be clearly understood that the same were merely for the purpose of illustration and that changes and modifications may readily be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter of the fluid blast type, means at least partially of insulating material defining an orifice, a pair of-'rin g-shaped contacts positioned on opposite sides of the orifice at least in the fully open circuit position of the interrupter, means for drawing an are through the orifice with its terminal ends disposed at the ring-shaped contacts, means for rotating the arc around the ring-shaped contacts while it is positioned within the orifice, means for forcing a blast of fluid through the orifice, and an insulating fluid directing member fixed to one of the ring-shaped contacts and extending at least partially within the orifice beyond the said one ring.- shaped contact during the interruption process to symmetrically direct the fluid blast on all sides of the last-mentioned contact.

2. In a circuit interrupter of type, means defining an orifice, a ring-shaped contact positioned on one side of the orifice at least in the fully open circuit position of the interrupter, means for drawing an arc through the orifice with one terminal end positioned at the ring-shaped contact, an insulating conicallyshaped fluid directing member projecting beyond thering-shaped contact at least partially within theorifice during the interruption process for symmetrically guiding the fluid blast through the orifice about the ring-shaped contact, and means for rotating the terminal end of the are around the ring-shaped contact.

3. In a circuit interrupter of the fluid blast type, means defining an orifice, a ring-shaped contact positioned on one side of the orifice at least in the fully open circuit position of the interrupter, means for drawing an are through the orifice with one terminal end thereof positioned at the ring-shaped contact, a conicallyshaped fluid directing member composed of insulating material extending beyond the ring shaped contact at least partially within the orifice and fixed by a magnetic stud to the ringshaped contact to symmetrically direct the fluid blast about the ring-shaped contact, and magnetic means for rotating'the terminal end of the are around the ring-shaped contact.

4. In a circuit interrupter of the fluid blast type, means defining an orifice, an annular sta-.

tionary contact disposed on a first side of the orifice, a stationary ring-shaped arcing contact disposed intermediate the annular stationary con tact and the orifice also on the first side of the orifice, a movable contact having a forward ringshaped arcing portion and a rearwardly flexible sleeve-like contacting portion movable from the second side of the orifice through the orifice to the first side thereof so that in the closed circuit position of the interrupter the sleeve-like contacting portion of themovable contact makes resilient contacting engagement with the annular stationary contact, during the opening operation an arc is drawn between the forward ringshaped arcing portion of the movable contact and the stationary ring-shaped arcing contact, the sleeve-like contacting portion spreading outwardly sufiiciently enough to actually contact the stationary ring-shaped arcing contact after separation from the annular stationary contact, and radial magnetic field coil means connected between the two stationary contacts to cause rotation of the arc.

5. In a circuit interrupter of the fluid blast type, means defining an orifice, an annular 'stationary contact disposed on a first side oi the portion of the movable contact and the stationthe fluid blast ary ring-shaped arcing contact, and coil means electrically connected between the annular stationary contact and the stationary ring-shaped arcing contact to rotate the arc around the ringshaped arcing portion of the movable contact and the stationary ring-shaped arcing contact while it is positioned within the orifice.

6. In a circuit interrupter of the fluid blast type,,means defining an orifice, an annular stationary contact disposed on a firstside of the orifice, a stationary ring-shaped arcing contact disposed intermediate the annular stationary contact and the orifice also on the first side of the orifice, a radial magnetic field coil connected between the aforesaid two contacts, a movable contact having a forward ring-shaped-arcing portion and a rearward annular contacting por-' tion movable from the second side of the orifice through the orifice to the first side thereof so that in the closed circuit position of the interrupter the annular contacting portion of the. movable contact makes contacting engagement with the annular stationary contact, during the opening operation an arc is drawn between the ring-shaped arcing portion of the movable contact and the stationary ring-shaped arcing contact to energize the coil and cause rotation of the are around said contacts, and an insulating conically-shaped follower member fixed to and movable with the ring-shaped arcing portion of the movable contact to symmetrically direct the fluid blast about the movable contact during the opening operation.

7. In a circuit interrupter of the fluid blast type, means defining an orifice, a ring-shaped contact positioned on the discharge side of the orifice closely adjacent to the point'of maximum restriction through the orifice at least in the open circuit position of the interrupter, means for establishing an arc within the orifice with one terminal thereof'terminating at the ring-shaped contactpmeans for rotating the terminal end of the arc around the ring-shaped contact, and

means for forcing fluid through the orifice in the direction of the ring-shaped contact.

8. In a circuit interrupter of the fluid blast type, means defining an orifice, a pair of cooperable ring-shaped contacts positioned on opposite sides of the orifice at least in the fully open circult position of the interrupter, at least one of the ring-shaped contacts being positioned closely adjacent the point of maximum restriction on the discharge side of the orifice, means for forc-' ing a blast of fluid through the orifice in the direction of said one ring-shaped contact, means for establishing an are between the pair of ringshaped contacts, and means for rotating the are around the pair of ring-shaped contacts while it is located within the orifice.

ALBERT P. STROM.

(References on following page) 9 REFERENCES CITED The following references are'of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 649,554 Schwedtmann May 15, 1900 730,704 Read June 9, 1903 991,480 Christensen May 9, 1911 Number 10 Name Date Prince Dec. 24, 1935 Hampton et a1 Aug. 18, 1936 Koppelmann et a1. Nov. 24, 1936 Biermanns et a1. Dec. 13, 1938 Balachowsky May 16, 1939 Rawlins Sept. 1, 1942 Ludwig et a1 Mar. 9, 1943 Scott Oct. 10, 1944 

